In modern integrated circuits, such as microcontrollers, microprocessors, and randomly accessed memories (RAM), the integrated circuits (ICs) are typically provided with more than one power signal (e.g. a standby power signal and a normal operation power signal, etc.). A first power supply signal is used for normal functional mode IC operation (e.g. VDD), while a second power supply signal is used as a backup power supply for standby mode IC operation (e.g. VSTBY). In modern designs, the entire memory array within the integrated circuit (IC) is either backed up by the backup power supply or it is not backed up by the backup power supply. Therefore, if the first power supply signal fails and the memory array is backed up by the second power supply signal, then data that was stored in the memory array prior to the power failure is retained in the memory array. However, if the first power supply signal fails and the memory array is not backed up by the second power supply signal, then data that was stored in the memory array prior to the power failure is lost. When using this inflexible system, a user of the integrated circuit (IC) is always in the situation where all the data stored in memory array is either lost or retained when the first power signal fails. There is no flexibility in this system such that certain portions of the memory are backed up by the second power supply signal while another portion of the memory is not backed up by the second power supply signal. Thus, memory backup cannot be performed on a piece-meal programmable basis. Therefore, this lack of flexibility impacts the power consumed by the part and the ability for wide applicability and flexibility of the integrated circuit (IC).
Therefore, the need exists for a method that allows a standby power signal (or low power signal) to be selectively coupled to a bank or block of memory in a memory array comprising a plurality of banks or blocks of memory. This added functionality is desirable to allow for enhanced IC power management, selective data retention management, and more flexible power loss response.